The present invention relates to imaging devices and, more particularly, to high-dynamic-range imaging systems.
Image sensors are commonly used in electronic devices such as cellular telephones, cameras, and computers to capture images. In a typical arrangement, an electronic device is provided with an image sensor having an array of image pixels and a corresponding lens. Some electronic devices use arrays of image sensors and arrays of corresponding lenses.
In certain applications, it may be desirable to capture high-dynamic range images. While highlight and shadow detail may be lost using a conventional image sensor, highlight and shadow detail may be retained using image sensors with high-dynamic-range imaging capabilities.
Common high-dynamic-range (HDR) imaging systems use multiple images that are captured by the image sensor, each image having a different exposure time. Captured short-exposure images may retain highlight detail while captured long-exposure images may retain shadow detail. In a typical device, image pixel values from short-exposure images and long-exposure images are selected to create an HDR image. Capturing multiple images can take an undesirable amount of time and/or memory.
In some devices, HDR images are generated by capturing a single interleaved long-exposure and short-exposure image in which alternating pairs of rows of pixels are exposed for alternating long and short integration times. The long-exposure rows are used to generate an interpolated long-exposure image and the short-exposure rows are used to generated an interpolated short-exposure image. A high-dynamic-range image can then be generated from the interpolated images.
However, because this type of row interleaved image capture method captures long-exposure image data and short-exposure image data separated by the time it takes to read out multiple pixel rows, HDR images generated in this may include artifacts as motion artifacts and row temporal noise artifacts.
It would therefore be desirable to provide improved imaging systems for high-dynamic-range imaging.